Question

Find the lateral area for the pyramid with the equilateral base

Answer 1

The lateral area for the pyramid with the equilateral base is 144 square units

Solution:

The given pyramid has 3 lateral triangular side

The figure is attached below

Base of triangle = 12 unit

Find the perpendicular

By Pythagoras theorem

$hypotenuse^2 = opposite^2 + adjacent^2$

Therefore,

$opposite^2 = 10^2 - 6^2\\\\opposite^2 = 100 - 36\\\\opposite^2 = 64\\\\opposite = 8$

Find the lateral surface area of 1 triangle

$\text{ Area of 1 lateral triangle } = \frac{1}{2} \times opposite \times base$

$\text{ Area of 1 lateral triangle } = \frac{1}{2} \times 8 \times 12\\\\\text{ Area of 1 lateral triangle } = 48$

Thus, lateral surface area of 3 triangle is:

3 x 48 = 144

Thus lateral area for the pyramid with the equilateral base is 144 square units